This invention relates to louvre windows, and in particular to blade holders for louvre windows of the kind comprising a rectangular window frame structure on opposite side elements of which are pivotally mounted a plurality of blade holders, there being provided a plurality of elongated louvre blades extending across the frame structure and having their opposite end edges held in opposing blade holders so that the blades may be pivoted about their longitudinal axes.
In this specification the term "inwardly", when used in relation to a blade holder, will mean the direction towards the corresponding and opposing blade holder.
One weakness of known designs of louvre window is that it is possible to remove an individual louvre blade due to the fact that the blades are supported only at their two ends. Depending on the strength of the materials used and the design of the blade holders, it is usually possible to remove those parts of the blade holders which retain the blades, by sawing or otherwise rupturing the blade holder so that the blade, which is usually of glass, may be slid out of the holders to give unauthorised access through the window. The object of the invention is to provide blade holders where, even if the holders are damaged, the blade held by them will remain in position, thus preventing access through the window unless the blade itself is broken.